The Imaging Core uses a wide variety of visualization techniques to extract morphologic and physiologic information from biological materials. The Core is structured at 6 facilities, each offering specialized services. 1. Through the HISTOLOGY FACILITY investigators have tissues fixed, sectioned, and stained for light microscopy. 2. The ULTRASTRUCTURE FACILITY processes tissues for transmission and/or scanning electron microscopy. 3. The IN SITU HYBRIDIZATION FACILITY processes tissues to determine the cellular distribution of mRNA using in situ hybridization techniques. 4. The VIDEO MICROSCOPY FACILITY houses 3 research-grade microscopes specially equipped for general viewing, for quantitation of fluorescence, and for various other measurements. 5. The MICROFLUORIMETRY FACILITY possesses a microscope connected to a spectrofluorimeter which allows investigators to measure fluorescence at higher gain and temporal resolution than is available by video microscopy. 6. The CONFOCAL MICROSCOPE FACILITY allows users to view their cells with confocal microscopy for precise Z-axis localization of fluorescent-labeled proteins. The Imaging Core also possesses digital image processing workstations allowing investigators to quantify images in various ways to output high-quality prints of these images for presentation purposes.